Switch to purely namespaced enums

This breaks code that referred to variant names in the same namespace as
their enum. Reexport the variants in the old location or alter code to
refer to the new locations:

```
pub enum Foo {
    A,
    B
}

fn main() {
    let a = A;
}
```
=>
```
pub use self::Foo::{A, B};

pub enum Foo {
    A,
    B
}

fn main() {
    let a = A;
}
```
or
```
pub enum Foo {
    A,
    B
}

fn main() {
    let a = Foo::A;
}
```

[breaking-change]

Author: sfackler

src/compiletest/common.rs

@@ -7,6 +7,7 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
+pub use self::Mode::*;
 
 use std::fmt;
 use std::str::FromStr;

src/compiletest/compiletest.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 #![crate_type = "bin"]
-#![feature(phase, slicing_syntax)]
+#![feature(phase, slicing_syntax, globs)]
 
 #![deny(warnings)]